Hi, my one month old son has just developed a rather odd sore on his genitalia. On the left side of his sac he has a deep crease, that is red and appears quite sore. It is a semi circle. It wasn t there when I changed his diaper this morning, so it showed up pretty quickly and all of a sudden. Is this just a regular rash? It seemed like it might be, but the deep crease is what had me worried...